1. Field of the Invention
The present invention relates to an information output apparatus, an information output method, and an information output program, which output information received, and an information transmitting apparatus, an information transmitting method, and an information transmitting program, which transmit information, and also relates to an information output system having the information output apparatus and the information transmitting apparatus.
2. Description of the Related Art
With diffusion of communications using the Internet, sales promotion and advertising via the Internet have been becoming increasingly active.
Conventionally, client-server systems are used to distribute information, such as advertisements via various networks including the Internet. A client-server system includes a server providing information and clients receiving the information from the server. In this system, the relationship between the information providing side and the information receiving side is simple in the sense that only the information providing side, i.e. the server is too heavily loaded.
Solutions to this problem with the client-server system include P-to-P (Peer to Peer) systems. A P-to-P system does not include components corresponding to a server and a client PC (personal computer) as used in a client-server system, but is comprised of a plurality of peers, each of which has the functions of both a server and a client PC. The P-to-P system is characterized in that the information providing side and the information receiving side are equal, and thus their loads are distributed over the entire network involved.
The P-to-P systems include a hybrid type and a pure type.
FIG. 9A is a diagram showing the configuration of a hybrid type P-to-P system.
In the hybrid type P-to-P system, user PCs 101 to 103 are connected to a core server 100 to transmit file lists stored in the PCs 101 to 103 to the server 100. The user PCs share the file lists, so that each of the user PCs searches the core server 100 for a file of another user PC, and thereafter the user PCs exchange the files directly.
FIG. 9B is a diagram showing the configuration of a pure type P-to-P system.
In FIG. 9B, the pure type P-to-P system is comprised of PCs 110, 111, and 112 through which information is transmitted.
As information distribution systems employing the pure type P-to-P system which distribute information such as advertisements, an information distribution system has been proposed, which pays attention to the similarity between the profiles of users to which the information is distributed and is capable of distributing information to users with similar interests to those of users who showed interest in particular information (e.g. Japanese Laid-Open Patent Publication (Kokai) No. 2002-298007).
In this proposed information distribution system employing the pure type P-to-P system, information distribution is carried out such that information is sequentially transmitted from one of a plurality of peers to another within a range determined by TTL (Time to Live) which is arbitrarily set to a value indicative of how many peers ahead the information is to be transmitted to.
A source peer that distributes information sets a predetermined value as the TTL, and a peer that has received the information decrements by 1 the TTL value attached to the information, and transmits the information and the decremented TTL value to a next peer. This sequential transmission of the information continues until the TTL value becomes zero.
It should be noted that a peer means a PC on which application software of the pure type P-to-P system is executed.
However, in the above-mentioned conventional pure type P-to-P system, the distribution range for information is determined by the TTL indicative of how many peers ahead the information should be transmitted to, and thus the distribution range cannot be set based on a physical distribution range or transmission distance in order to meet needs, such as the user of a source peer wishing to distribute information to peers within a 2-kilometer radius from the source peer, or only to peers within a transmission distance of 2 kilometers.
For example, let it be assumed that there are peers A and B in the above-mentioned conventional pure type P-to-P system and the peer A is away from the source peer a transmission distance of 1 kilometer and the peer B a transmission distance of 10 kilometers, with the TTL set to 1. In such a situation, even if the user of the source peer wishes to distribute information to the peer within a 2-kilometer radius, or to the peer within a transmission distance of 2 kilometers, the system does distribute the information to both the peers.